<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 链接未访问状态 */
        a:link {
            color: green;
            /* 去掉下划线 */
            text-decoration: none;
        }

        /* 链接访问过的状态 */
        a:visted {
            color: orange
        }

        /* 链接鼠标悬停状态 */
        a:hover {
            color: red;
            text-decoration: underline;
        }

        /* 链接激活状态 */
        a:active {
            color: blue;
        }
    </style>
</head>

<body>
    <a href="#">百度</a>
</body>

</html>